|
6L6 single tube transmitter
I came across a cute little homebrew CW transmitter utilizing only a
single 6L6. Mostly made from radio and audio junkbox parts, it does seem to work. I put it on the air briefly with its 40 meter Xtal and monitored the signal on another antenna. Sounds kind of chirpy, actually worse than chirpy. Needs some kind of work or upgrade or correction. I did some web searching but could not actually come up with a schematic for this rig, probably out of some old magazine or something. I do not quite understand how it works without a power supply rectifier. There is nothing under the hood which looks like a diode or selenium rectifier. Anyone have a clue as to this circuit. I am kind of new to this. How might I proceed to make this little rig into a useable QRP unit. I think it probably makes something under 10 watts, and the cw sounds goofy, wimpy, and wobbly. It is someone's old nice lay out failure, but it would be a fun challenge to convert it into something useful. Anyone seen a circuit for a singl 6L6 rig?...who knows maybe it has the wrong tube in there. Hmmmm....how to do the detective work on this???? I have a certain nostalgia for simple one tube rigs, when I was a novice in the early 50s as a kid I built this crazy rig with a single 117N7 that worked great with my very compromised end-fed random wire. I have recently found the schematic for that one, but it seems kind of crazy to build that one again, but who knows....the schematic for the 117N7 rig can be found on page 38 of "Radio For The Millions", 1945 Popular Science Publishing Co. Inc. This illustration has the chassis plugged into the AC neutral/gound side. Another variation appears on page 105 in "Ham Radio Projects" 1968 by Bert Simon, a circuit which looks even more scarry since you only plug into the hot leg of the AC outlet, and then ground the chassis to earth ground. I do not know how I lived to tell you now that it was my first rig! There is a one-tube rig on page 99 of "Ham Projects..." which uses a 6AV5 but that is not the circuit I see in this unkown 6L6 rig. Let me know if you know of a source for this single 6L6 transmitter. Nothing in either of the books mentioned has one like this. Other clues: it has three rf (air core) chokes, no other iron core choke, uses two variable condensers, keys thru one of these chokes to pin 8. Another choke goes from the antenna center pin to the chassis ground. The 3 rf chokes used appear to be identical. Bill / K6TAJ |
"zeno" wrote in message ...
I came across a cute little homebrew CW transmitter utilizing only a single 6L6. Mostly made from radio and audio junkbox parts, it does seem to work. I put it on the air briefly with its 40 meter Xtal and monitored the signal on another antenna. Sounds kind of chirpy, actually worse than chirpy. Needs some kind of work or upgrade or correction. [snip] Anyone seen a circuit for a singl 6L6 rig?...who knows maybe it has the wrong tube in there. Hmmmm....how to do the detective work on this???? [snip] There is a one-tube rig on page 99 of "Ham Projects..." which uses a 6AV5 but that is not the circuit I see in this unkown 6L6 rig. Let me know if you know of a source for this single 6L6 transmitter. Nothing in either of the books mentioned has one like this. Other clues: it has three rf (air core) chokes, no other iron core choke, uses two variable condensers, keys thru one of these chokes to pin 8. Another choke goes from the antenna center pin to the chassis ground. The 3 rf chokes used appear to be identical. Bill / K6TAJ Bill - I seem to remember the ARRL Handbooks having a 6L6 based circuit. Have you searched for the MEISSNER NOVICE TRANSMITTER ? I think it used a 6L6 oscillator Have you seem the Ameco AC-1 web pages? http://www.qsl.net/wb1gfh/ameco.html If you solid state the rectifier, then its also one-tube ! Greg w9gb |
"zeno" wrote in message ...
I came across a cute little homebrew CW transmitter utilizing only a single 6L6. Mostly made from radio and audio junkbox parts, it does seem to work. I put it on the air briefly with its 40 meter Xtal and monitored the signal on another antenna. Sounds kind of chirpy, actually worse than chirpy. Needs some kind of work or upgrade or correction. [snip] Anyone seen a circuit for a singl 6L6 rig?...who knows maybe it has the wrong tube in there. Hmmmm....how to do the detective work on this???? [snip] There is a one-tube rig on page 99 of "Ham Projects..." which uses a 6AV5 but that is not the circuit I see in this unkown 6L6 rig. Let me know if you know of a source for this single 6L6 transmitter. Nothing in either of the books mentioned has one like this. Other clues: it has three rf (air core) chokes, no other iron core choke, uses two variable condensers, keys thru one of these chokes to pin 8. Another choke goes from the antenna center pin to the chassis ground. The 3 rf chokes used appear to be identical. Bill / K6TAJ Bill - I seem to remember the ARRL Handbooks having a 6L6 based circuit. Have you searched for the MEISSNER NOVICE TRANSMITTER ? I think it used a 6L6 oscillator Have you seem the Ameco AC-1 web pages? http://www.qsl.net/wb1gfh/ameco.html If you solid state the rectifier, then its also one-tube ! Greg w9gb |
Anyone seen a circuit for a singl 6L6 rig?...who
knows maybe it has the wrong tube in there. Hmmmm....how to do the detective work on this???? Zeno ...sound like the one I built in 65 from the ham section in PE mag. I tried to get someone to answer my CQs for 2 weeks with no reply ...then I got a guy about 5 miles away...success then I got a card from an OO in Oregon. I was proud of that card ...showed everyone what my 6L6 would do. God Bless and Merry Christmas .... KI3R Tom Popovic Belle Vernon Pa. |
Anyone seen a circuit for a singl 6L6 rig?...who
knows maybe it has the wrong tube in there. Hmmmm....how to do the detective work on this???? Zeno ...sound like the one I built in 65 from the ham section in PE mag. I tried to get someone to answer my CQs for 2 weeks with no reply ...then I got a guy about 5 miles away...success then I got a card from an OO in Oregon. I was proud of that card ...showed everyone what my 6L6 would do. God Bless and Merry Christmas .... KI3R Tom Popovic Belle Vernon Pa. |
"zeno" wrote in message ...
I came across a cute little homebrew CW transmitter utilizing only a single 6L6. Mostly made from radio and audio junkbox parts, it does seem to work. I put it on the air briefly with its 40 meter Xtal and monitored the signal on another antenna. Sounds kind of chirpy, actually worse than chirpy. Bill / K6TAJ Bill - I just did a Google.com search for: "6L6 transmitter" and I same up with several links and schematics. From notes, it appears several designs were published pre-WW2 in QST. RCA introduced the 6L6 tube in early 1936 as an audio power tube. Are you looking at a Stancor 25-B transmitter, photo in article he http://www.io.com/~nielw/6l6/6L6.htm W0VLZ built the Stancor 10P, which is listed in the 1940, 5th edition of the Stancor Hamanual http://www.io.com/~nielw/2tube_xmtr/2tube_xmtr.htm K4GC homebuilt 6L6 http://www.qsl.net/k4gc/6L6.html K5DH 40 meter version built from design in "104 Ham Radio Projects for Novice and Technician"; TAB Books, 1968 http://www.qsl.net/k5dh/6ag7_6l6.html October 2004 issue of CQ magazine featured a 6L6 transmitter (with a correction in the December 2004 issue under "World of Ideas") LA6NCA Norwegian homebrew http://www.laud.no/la6nca/homebrew/ 6CL6 http://faculty.frostburg.edu/phys/la.../6cl6xmtr.html http://www.tube.be/6l6.html w9gb |
"zeno" wrote in message ...
I came across a cute little homebrew CW transmitter utilizing only a single 6L6. Mostly made from radio and audio junkbox parts, it does seem to work. I put it on the air briefly with its 40 meter Xtal and monitored the signal on another antenna. Sounds kind of chirpy, actually worse than chirpy. Bill / K6TAJ Bill - I just did a Google.com search for: "6L6 transmitter" and I same up with several links and schematics. From notes, it appears several designs were published pre-WW2 in QST. RCA introduced the 6L6 tube in early 1936 as an audio power tube. Are you looking at a Stancor 25-B transmitter, photo in article he http://www.io.com/~nielw/6l6/6L6.htm W0VLZ built the Stancor 10P, which is listed in the 1940, 5th edition of the Stancor Hamanual http://www.io.com/~nielw/2tube_xmtr/2tube_xmtr.htm K4GC homebuilt 6L6 http://www.qsl.net/k4gc/6L6.html K5DH 40 meter version built from design in "104 Ham Radio Projects for Novice and Technician"; TAB Books, 1968 http://www.qsl.net/k5dh/6ag7_6l6.html October 2004 issue of CQ magazine featured a 6L6 transmitter (with a correction in the December 2004 issue under "World of Ideas") LA6NCA Norwegian homebrew http://www.laud.no/la6nca/homebrew/ 6CL6 http://faculty.frostburg.edu/phys/la.../6cl6xmtr.html http://www.tube.be/6l6.html w9gb |
Thanks for the links. What is unusual about the transmitter in question is that
it has one tube total, no rectifier, no apparent power supply section besides the power transformer and an electrolytic can. No chokes other than the 3 rf air wound chokes. It came with a 6L6, I cannot be sure that is what it calls for, but it did work, although with "wobbly" goofy signal. I have not come across a design with only one 6L6 total although I have heard that such things exist. I did the same google search you did when I first got this thing. Bill/ K6TAJ w9gb wrote: "zeno" wrote in message ... I came across a cute little homebrew CW transmitter utilizing only a single 6L6. Mostly made from radio and audio junkbox parts, it does seem to work. I put it on the air briefly with its 40 meter Xtal and monitored the signal on another antenna. Sounds kind of chirpy, actually worse than chirpy. Bill / K6TAJ Bill - I just did a Google.com search for: "6L6 transmitter" and I same up with several links and schematics. From notes, it appears several designs were published pre-WW2 in QST. RCA introduced the 6L6 tube in early 1936 as an audio power tube. Are you looking at a Stancor 25-B transmitter, photo in article he http://www.io.com/~nielw/6l6/6L6.htm W0VLZ built the Stancor 10P, which is listed in the 1940, 5th edition of the Stancor Hamanual http://www.io.com/~nielw/2tube_xmtr/2tube_xmtr.htm K4GC homebuilt 6L6 http://www.qsl.net/k4gc/6L6.html K5DH 40 meter version built from design in "104 Ham Radio Projects for Novice and Technician"; TAB Books, 1968 http://www.qsl.net/k5dh/6ag7_6l6.html October 2004 issue of CQ magazine featured a 6L6 transmitter (with a correction in the December 2004 issue under "World of Ideas") LA6NCA Norwegian homebrew http://www.laud.no/la6nca/homebrew/ 6CL6 http://faculty.frostburg.edu/phys/la.../6cl6xmtr.html http://www.tube.be/6l6.html w9gb |
Thanks for the links. What is unusual about the transmitter in question is that
it has one tube total, no rectifier, no apparent power supply section besides the power transformer and an electrolytic can. No chokes other than the 3 rf air wound chokes. It came with a 6L6, I cannot be sure that is what it calls for, but it did work, although with "wobbly" goofy signal. I have not come across a design with only one 6L6 total although I have heard that such things exist. I did the same google search you did when I first got this thing. Bill/ K6TAJ w9gb wrote: "zeno" wrote in message ... I came across a cute little homebrew CW transmitter utilizing only a single 6L6. Mostly made from radio and audio junkbox parts, it does seem to work. I put it on the air briefly with its 40 meter Xtal and monitored the signal on another antenna. Sounds kind of chirpy, actually worse than chirpy. Bill / K6TAJ Bill - I just did a Google.com search for: "6L6 transmitter" and I same up with several links and schematics. From notes, it appears several designs were published pre-WW2 in QST. RCA introduced the 6L6 tube in early 1936 as an audio power tube. Are you looking at a Stancor 25-B transmitter, photo in article he http://www.io.com/~nielw/6l6/6L6.htm W0VLZ built the Stancor 10P, which is listed in the 1940, 5th edition of the Stancor Hamanual http://www.io.com/~nielw/2tube_xmtr/2tube_xmtr.htm K4GC homebuilt 6L6 http://www.qsl.net/k4gc/6L6.html K5DH 40 meter version built from design in "104 Ham Radio Projects for Novice and Technician"; TAB Books, 1968 http://www.qsl.net/k5dh/6ag7_6l6.html October 2004 issue of CQ magazine featured a 6L6 transmitter (with a correction in the December 2004 issue under "World of Ideas") LA6NCA Norwegian homebrew http://www.laud.no/la6nca/homebrew/ 6CL6 http://faculty.frostburg.edu/phys/la.../6cl6xmtr.html http://www.tube.be/6l6.html w9gb |
Maybe yours was the mystery circuit. Did yours have only one 6L6 and nothing
else, I mean no power supply rectifier? This rig does not even have a diode or selenium under the hood, how can they do that? Do I have AC for the B+? I am not an EE. What am I missing here? What mysteries lurk in the 6L6 that we mortals do not fathom? Beam me up. Bill / K6TAJ garigue wrote: Anyone seen a circuit for a singl 6L6 rig?...who knows maybe it has the wrong tube in there. Hmmmm....how to do the detective work on this???? Zeno ...sound like the one I built in 65 from the ham section in PE mag. I tried to get someone to answer my CQs for 2 weeks with no reply ...then I got a guy about 5 miles away...success then I got a card from an OO in Oregon. I was proud of that card ...showed everyone what my 6L6 would do. God Bless and Merry Christmas .... KI3R Tom Popovic Belle Vernon Pa. |
Maybe yours was the mystery circuit. Did yours have only one 6L6 and nothing
else, I mean no power supply rectifier? This rig does not even have a diode or selenium under the hood, how can they do that? Do I have AC for the B+? I am not an EE. What am I missing here? What mysteries lurk in the 6L6 that we mortals do not fathom? Beam me up. Bill / K6TAJ garigue wrote: Anyone seen a circuit for a singl 6L6 rig?...who knows maybe it has the wrong tube in there. Hmmmm....how to do the detective work on this???? Zeno ...sound like the one I built in 65 from the ham section in PE mag. I tried to get someone to answer my CQs for 2 weeks with no reply ...then I got a guy about 5 miles away...success then I got a card from an OO in Oregon. I was proud of that card ...showed everyone what my 6L6 would do. God Bless and Merry Christmas .... KI3R Tom Popovic Belle Vernon Pa. |
Bill,
It sounds like you've been around awhile and have built some stuff in the past. Surely you can look at the circuit and figure out what is powering the thing. Put your meter into that thing and start measuring voltages (from the line cord, through the transformer and on...) Of course, if you find "any" DC - you've got a diode someplace. Take some paper and draw out the schematic (can't be to hard for one tube circuit). That will show you what you have. Check the tube base wiring against the 6L6 and see if everything goes to the correct pins for such a tube. It's possible you should have a tube which sports a rectifier (diode section) and another tube in the same envelope). At any rate - a part by part inspection resulting in a schematic will tell all! It's rather elementary. I'd be interested to hear what you find. Good luck, Roger, KL7Q zeno wrote in message ... I came across a cute little homebrew CW transmitter utilizing only a single 6L6. Mostly made from radio and audio junkbox parts, it does seem to work. I put it on the air briefly with its 40 meter Xtal and monitored the signal on another antenna. Sounds kind of chirpy, actually worse than chirpy. Needs some kind of work or upgrade or correction. I did some web searching but could not actually come up with a schematic for this rig, probably out of some old magazine or something. I do not quite understand how it works without a power supply rectifier. There is nothing under the hood which looks like a diode or selenium rectifier. Anyone have a clue as to this circuit. I am kind of new to this. How might I proceed to make this little rig into a useable QRP unit. I think it probably makes something under 10 watts, and the cw sounds goofy, wimpy, and wobbly. It is someone's old nice lay out failure, but it would be a fun challenge to convert it into something useful. Anyone seen a circuit for a singl 6L6 rig?...who knows maybe it has the wrong tube in there. Hmmmm....how to do the detective work on this???? I have a certain nostalgia for simple one tube rigs, when I was a novice in the early 50s as a kid I built this crazy rig with a single 117N7 that worked great with my very compromised end-fed random wire. I have recently found the schematic for that one, but it seems kind of crazy to build that one again, but who knows....the schematic for the 117N7 rig can be found on page 38 of "Radio For The Millions", 1945 Popular Science Publishing Co. Inc. This illustration has the chassis plugged into the AC neutral/gound side. Another variation appears on page 105 in "Ham Radio Projects" 1968 by Bert Simon, a circuit which looks even more scarry since you only plug into the hot leg of the AC outlet, and then ground the chassis to earth ground. I do not know how I lived to tell you now that it was my first rig! There is a one-tube rig on page 99 of "Ham Projects..." which uses a 6AV5 but that is not the circuit I see in this unkown 6L6 rig. Let me know if you know of a source for this single 6L6 transmitter. Nothing in either of the books mentioned has one like this. Other clues: it has three rf (air core) chokes, no other iron core choke, uses two variable condensers, keys thru one of these chokes to pin 8. Another choke goes from the antenna center pin to the chassis ground. The 3 rf chokes used appear to be identical. Bill / K6TAJ |
Bill,
It sounds like you've been around awhile and have built some stuff in the past. Surely you can look at the circuit and figure out what is powering the thing. Put your meter into that thing and start measuring voltages (from the line cord, through the transformer and on...) Of course, if you find "any" DC - you've got a diode someplace. Take some paper and draw out the schematic (can't be to hard for one tube circuit). That will show you what you have. Check the tube base wiring against the 6L6 and see if everything goes to the correct pins for such a tube. It's possible you should have a tube which sports a rectifier (diode section) and another tube in the same envelope). At any rate - a part by part inspection resulting in a schematic will tell all! It's rather elementary. I'd be interested to hear what you find. Good luck, Roger, KL7Q zeno wrote in message ... I came across a cute little homebrew CW transmitter utilizing only a single 6L6. Mostly made from radio and audio junkbox parts, it does seem to work. I put it on the air briefly with its 40 meter Xtal and monitored the signal on another antenna. Sounds kind of chirpy, actually worse than chirpy. Needs some kind of work or upgrade or correction. I did some web searching but could not actually come up with a schematic for this rig, probably out of some old magazine or something. I do not quite understand how it works without a power supply rectifier. There is nothing under the hood which looks like a diode or selenium rectifier. Anyone have a clue as to this circuit. I am kind of new to this. How might I proceed to make this little rig into a useable QRP unit. I think it probably makes something under 10 watts, and the cw sounds goofy, wimpy, and wobbly. It is someone's old nice lay out failure, but it would be a fun challenge to convert it into something useful. Anyone seen a circuit for a singl 6L6 rig?...who knows maybe it has the wrong tube in there. Hmmmm....how to do the detective work on this???? I have a certain nostalgia for simple one tube rigs, when I was a novice in the early 50s as a kid I built this crazy rig with a single 117N7 that worked great with my very compromised end-fed random wire. I have recently found the schematic for that one, but it seems kind of crazy to build that one again, but who knows....the schematic for the 117N7 rig can be found on page 38 of "Radio For The Millions", 1945 Popular Science Publishing Co. Inc. This illustration has the chassis plugged into the AC neutral/gound side. Another variation appears on page 105 in "Ham Radio Projects" 1968 by Bert Simon, a circuit which looks even more scarry since you only plug into the hot leg of the AC outlet, and then ground the chassis to earth ground. I do not know how I lived to tell you now that it was my first rig! There is a one-tube rig on page 99 of "Ham Projects..." which uses a 6AV5 but that is not the circuit I see in this unkown 6L6 rig. Let me know if you know of a source for this single 6L6 transmitter. Nothing in either of the books mentioned has one like this. Other clues: it has three rf (air core) chokes, no other iron core choke, uses two variable condensers, keys thru one of these chokes to pin 8. Another choke goes from the antenna center pin to the chassis ground. The 3 rf chokes used appear to be identical. Bill / K6TAJ |
"Roger and Ute Brown" ) writes: Check the tube base wiring against the 6L6 and see if everything goes to the correct pins for such a tube. It's possible you should have a tube which sports a rectifier (diode section) and another tube in the same envelope). At any rate - a part by part inspection resulting in a schematic will tell all! I thought of that myself. While this transmitter is so simple it has to be pretty generic, so there doesn't have to be an article about it, I have seen "single tube" transmitters described in old magazines that used something intended for AC/DC use, ie a power stage with a built in rectifier that used a high filament voltage. I'm thinking 50L6, but I'm not sure if that is right. I don't remember if there was something in an octal package that ran off 117volts directly. I don't think the original poster mentioned if there was a transformer, and somehow I suspect the lack of one would be a greater indicator of this route. Of course, selenium recitifiers may have had a brief enough life that someone might not recognize one by sight. Michael VE2BVW |
"Roger and Ute Brown" ) writes: Check the tube base wiring against the 6L6 and see if everything goes to the correct pins for such a tube. It's possible you should have a tube which sports a rectifier (diode section) and another tube in the same envelope). At any rate - a part by part inspection resulting in a schematic will tell all! I thought of that myself. While this transmitter is so simple it has to be pretty generic, so there doesn't have to be an article about it, I have seen "single tube" transmitters described in old magazines that used something intended for AC/DC use, ie a power stage with a built in rectifier that used a high filament voltage. I'm thinking 50L6, but I'm not sure if that is right. I don't remember if there was something in an octal package that ran off 117volts directly. I don't think the original poster mentioned if there was a transformer, and somehow I suspect the lack of one would be a greater indicator of this route. Of course, selenium recitifiers may have had a brief enough life that someone might not recognize one by sight. Michael VE2BVW |
Michael Black wrote:
I thought of that myself. While this transmitter is so simple it has to be pretty generic, so there doesn't have to be an article about it, I have seen "single tube" transmitters described in old magazines that used something intended for AC/DC use, ie a power stage with a built in rectifier that used a high filament voltage. I'm thinking 50L6, but I'm not sure if that is right. I don't remember if there was something in an octal package that ran off 117volts directly. The 117L7 has a built-in diode section. Here's an xmtr made with one. http://antiqueradio.org/lil7.htm -Bill |
Michael Black wrote:
I thought of that myself. While this transmitter is so simple it has to be pretty generic, so there doesn't have to be an article about it, I have seen "single tube" transmitters described in old magazines that used something intended for AC/DC use, ie a power stage with a built in rectifier that used a high filament voltage. I'm thinking 50L6, but I'm not sure if that is right. I don't remember if there was something in an octal package that ran off 117volts directly. The 117L7 has a built-in diode section. Here's an xmtr made with one. http://antiqueradio.org/lil7.htm -Bill |
Michael,
Well - he said (in a subsequent post) that it had a transformer and electrolytic. I surmise from that he has DC running around somewhere since it apparently generates a signal. All one would need to do is trace the voltage from the secondary to the elusive rectifier. Or one should find DC across the electrolytic and be able to trace back towards the transformer from there. I'm sure he'll figure it out. If he has DC - he has a rectifier hidden someplace. If he doesn't - it can't work (as he says). Roger, KL7Q Michael Black wrote in message ... "Roger and Ute Brown" ) writes: Check the tube base wiring against the 6L6 and see if everything goes to the correct pins for such a tube. It's possible you should have a tube which sports a rectifier (diode section) and another tube in the same envelope). At any rate - a part by part inspection resulting in a schematic will tell all! I thought of that myself. While this transmitter is so simple it has to be pretty generic, so there doesn't have to be an article about it, I have seen "single tube" transmitters described in old magazines that used something intended for AC/DC use, ie a power stage with a built in rectifier that used a high filament voltage. I'm thinking 50L6, but I'm not sure if that is right. I don't remember if there was something in an octal package that ran off 117volts directly. I don't think the original poster mentioned if there was a transformer, and somehow I suspect the lack of one would be a greater indicator of this route. Of course, selenium recitifiers may have had a brief enough life that someone might not recognize one by sight. Michael VE2BVW |
Michael,
Well - he said (in a subsequent post) that it had a transformer and electrolytic. I surmise from that he has DC running around somewhere since it apparently generates a signal. All one would need to do is trace the voltage from the secondary to the elusive rectifier. Or one should find DC across the electrolytic and be able to trace back towards the transformer from there. I'm sure he'll figure it out. If he has DC - he has a rectifier hidden someplace. If he doesn't - it can't work (as he says). Roger, KL7Q Michael Black wrote in message ... "Roger and Ute Brown" ) writes: Check the tube base wiring against the 6L6 and see if everything goes to the correct pins for such a tube. It's possible you should have a tube which sports a rectifier (diode section) and another tube in the same envelope). At any rate - a part by part inspection resulting in a schematic will tell all! I thought of that myself. While this transmitter is so simple it has to be pretty generic, so there doesn't have to be an article about it, I have seen "single tube" transmitters described in old magazines that used something intended for AC/DC use, ie a power stage with a built in rectifier that used a high filament voltage. I'm thinking 50L6, but I'm not sure if that is right. I don't remember if there was something in an octal package that ran off 117volts directly. I don't think the original poster mentioned if there was a transformer, and somehow I suspect the lack of one would be a greater indicator of this route. Of course, selenium recitifiers may have had a brief enough life that someone might not recognize one by sight. Michael VE2BVW |
The transmitter can work without a separate rectifier. I recall a circuit
from the 30's in which the transmitter tube is used also as the rectifier. I think it was in the RCA handbook. I sort of recall an 813 tube, but that may have been a bit early for the 813. Even in those days, it was not "state of the art". Now, I will have to look for the circuit, but the oscillator tube can also serve as the rectifier. It complicates things a bit and is not in any of the Handbooks. Never have seen a 6L6 circuit configured that way, but it can be done and was done in the 30's in at least one circuit. Colin K7FM --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04 |
The transmitter can work without a separate rectifier. I recall a circuit
from the 30's in which the transmitter tube is used also as the rectifier. I think it was in the RCA handbook. I sort of recall an 813 tube, but that may have been a bit early for the 813. Even in those days, it was not "state of the art". Now, I will have to look for the circuit, but the oscillator tube can also serve as the rectifier. It complicates things a bit and is not in any of the Handbooks. Never have seen a 6L6 circuit configured that way, but it can be done and was done in the 30's in at least one circuit. Colin K7FM --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04 |
I am looking at "Practical Radio Telegraphy" dated 1928. The RCA P-8
transmitter is described with tube converter ET-3628. This converter is a tube replacement for the "quenched and synchrnous gaps formerly located on the power panel". it runs 1.5 kw using 2 tubes. One of the problems mentioned is "fading or swinging signals", in which it is stated that "such difficulties may be encountered in the case of a heavy sea causing variation of the antenna capacity by the rolling of the vessel ..." it is mentioned that if, on occasion, one tube burns out and there is no replacement, the circuit may be operated as a half wave rectifier with just one tube. Even more interesting is what to do if both tubes fail and no spares are available: "the operator may connect his transmitter in plain-aerial style. This is accomplished by removing all of the connections from the three secondary terminals of the plate transformer and connecting the antenna to one outside terminal of this transformer, and the ground to the other. The safety gap shunted across the secondary terminals will then function as an oscillatory spark discharger." DO NOT TRY THIS AT HOME. I PRESUME MORE THAN ONE SAILOR TRIED CLEANING BIRD POOP OFF THE TRANSMITTING AERIAL AND BECAME WELDED TO THE DECK WITH THIS SYSTEM. Using a Poulsen Tikker form of detection, this transmitter may not have sounded that much different from those that had dc on the plates. Colin K7FM --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04 |
I am looking at "Practical Radio Telegraphy" dated 1928. The RCA P-8
transmitter is described with tube converter ET-3628. This converter is a tube replacement for the "quenched and synchrnous gaps formerly located on the power panel". it runs 1.5 kw using 2 tubes. One of the problems mentioned is "fading or swinging signals", in which it is stated that "such difficulties may be encountered in the case of a heavy sea causing variation of the antenna capacity by the rolling of the vessel ..." it is mentioned that if, on occasion, one tube burns out and there is no replacement, the circuit may be operated as a half wave rectifier with just one tube. Even more interesting is what to do if both tubes fail and no spares are available: "the operator may connect his transmitter in plain-aerial style. This is accomplished by removing all of the connections from the three secondary terminals of the plate transformer and connecting the antenna to one outside terminal of this transformer, and the ground to the other. The safety gap shunted across the secondary terminals will then function as an oscillatory spark discharger." DO NOT TRY THIS AT HOME. I PRESUME MORE THAN ONE SAILOR TRIED CLEANING BIRD POOP OFF THE TRANSMITTING AERIAL AND BECAME WELDED TO THE DECK WITH THIS SYSTEM. Using a Poulsen Tikker form of detection, this transmitter may not have sounded that much different from those that had dc on the plates. Colin K7FM --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04 |
Colin,
That's really interesting. I was not aware that could be done. However, I would think that the chances that the 6L6 circuit was configured to work in that fashion are slim at best (but then one never knows). Thanks for the interesting information. Roger, KL7Q COLIN LAMB wrote in message ink.net... I am looking at "Practical Radio Telegraphy" dated 1928. The RCA P-8 transmitter is described with tube converter ET-3628. This converter is a tube replacement for the "quenched and synchrnous gaps formerly located on the power panel". it runs 1.5 kw using 2 tubes. One of the problems mentioned is "fading or swinging signals", in which it is stated that "such difficulties may be encountered in the case of a heavy sea causing variation of the antenna capacity by the rolling of the vessel ...." it is mentioned that if, on occasion, one tube burns out and there is no replacement, the circuit may be operated as a half wave rectifier with just one tube. Even more interesting is what to do if both tubes fail and no spares are available: "the operator may connect his transmitter in plain-aerial style. This is accomplished by removing all of the connections from the three secondary terminals of the plate transformer and connecting the antenna to one outside terminal of this transformer, and the ground to the other. The safety gap shunted across the secondary terminals will then function as an oscillatory spark discharger." DO NOT TRY THIS AT HOME. I PRESUME MORE THAN ONE SAILOR TRIED CLEANING BIRD POOP OFF THE TRANSMITTING AERIAL AND BECAME WELDED TO THE DECK WITH THIS SYSTEM. Using a Poulsen Tikker form of detection, this transmitter may not have sounded that much different from those that had dc on the plates. Colin K7FM --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04 |
Colin,
That's really interesting. I was not aware that could be done. However, I would think that the chances that the 6L6 circuit was configured to work in that fashion are slim at best (but then one never knows). Thanks for the interesting information. Roger, KL7Q COLIN LAMB wrote in message ink.net... I am looking at "Practical Radio Telegraphy" dated 1928. The RCA P-8 transmitter is described with tube converter ET-3628. This converter is a tube replacement for the "quenched and synchrnous gaps formerly located on the power panel". it runs 1.5 kw using 2 tubes. One of the problems mentioned is "fading or swinging signals", in which it is stated that "such difficulties may be encountered in the case of a heavy sea causing variation of the antenna capacity by the rolling of the vessel ...." it is mentioned that if, on occasion, one tube burns out and there is no replacement, the circuit may be operated as a half wave rectifier with just one tube. Even more interesting is what to do if both tubes fail and no spares are available: "the operator may connect his transmitter in plain-aerial style. This is accomplished by removing all of the connections from the three secondary terminals of the plate transformer and connecting the antenna to one outside terminal of this transformer, and the ground to the other. The safety gap shunted across the secondary terminals will then function as an oscillatory spark discharger." DO NOT TRY THIS AT HOME. I PRESUME MORE THAN ONE SAILOR TRIED CLEANING BIRD POOP OFF THE TRANSMITTING AERIAL AND BECAME WELDED TO THE DECK WITH THIS SYSTEM. Using a Poulsen Tikker form of detection, this transmitter may not have sounded that much different from those that had dc on the plates. Colin K7FM --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04 |
Deep down in my memory banks, I recall seeing an OSS transmitter from WWII
that used a similar circuit to avoid the failure of a rectifier tube, where the 6L6 was used as a rectifier also. It did make sense, since the rectifier tube was more fragile than the metal 6L6. Otherwise, it would make no sense, other than to confuse your buddy - like using a 6L6 for a rectifier and a 5U4 for the final output stage (sure it can be done). Colin K7FM --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04 |
Deep down in my memory banks, I recall seeing an OSS transmitter from WWII
that used a similar circuit to avoid the failure of a rectifier tube, where the 6L6 was used as a rectifier also. It did make sense, since the rectifier tube was more fragile than the metal 6L6. Otherwise, it would make no sense, other than to confuse your buddy - like using a 6L6 for a rectifier and a 5U4 for the final output stage (sure it can be done). Colin K7FM --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04 |
On closer examination again, I do now see a couple of small diodes (both have
the number 205) which were hiding behind some black spaghetti pushed up against them. This little homebrew seems to have been carefully assembled and I have no reason to believe that the 6L6 is not the correct tube. The little rig does work, but, as mentioned, the CW note was quite distorted and unacceptable. How would one go about trouble shooting this problem. At this point I have limited bench equipment , but might consider acquiring some. An oscilloscope is high on the want list. Can you point to a part of the circuit which would result in this very chirpy and wobbly CW tone. I would have to fire it up again to remember how best to describe the sound of this signal. Bill K6TAJ Roger and Ute Brown wrote: Bill, It sounds like you've been around awhile and have built some stuff in the past. Surely you can look at the circuit and figure out what is powering the thing. Put your meter into that thing and start measuring voltages (from the line cord, through the transformer and on...) Of course, if you find "any" DC - you've got a diode someplace. Take some paper and draw out the schematic (can't be to hard for one tube circuit). That will show you what you have. Check the tube base wiring against the 6L6 and see if everything goes to the correct pins for such a tube. It's possible you should have a tube which sports a rectifier (diode section) and another tube in the same envelope). At any rate - a part by part inspection resulting in a schematic will tell all! It's rather elementary. I'd be interested to hear what you find. Good luck, Roger, KL7Q zeno wrote in message ... I came across a cute little homebrew CW transmitter utilizing only a single 6L6. Mostly made from radio and audio junkbox parts, it does seem to work. I put it on the air briefly with its 40 meter Xtal and monitored the signal on another antenna. Sounds kind of chirpy, actually worse than chirpy. Needs some kind of work or upgrade or correction. I did some web searching but could not actually come up with a schematic for this rig, probably out of some old magazine or something. I do not quite understand how it works without a power supply rectifier. There is nothing under the hood which looks like a diode or selenium rectifier. Anyone have a clue as to this circuit. I am kind of new to this. How might I proceed to make this little rig into a useable QRP unit. I think it probably makes something under 10 watts, and the cw sounds goofy, wimpy, and wobbly. It is someone's old nice lay out failure, but it would be a fun challenge to convert it into something useful. Anyone seen a circuit for a singl 6L6 rig?...who knows maybe it has the wrong tube in there. Hmmmm....how to do the detective work on this???? I have a certain nostalgia for simple one tube rigs, when I was a novice in the early 50s as a kid I built this crazy rig with a single 117N7 that worked great with my very compromised end-fed random wire. I have recently found the schematic for that one, but it seems kind of crazy to build that one again, but who knows....the schematic for the 117N7 rig can be found on page 38 of "Radio For The Millions", 1945 Popular Science Publishing Co. Inc. This illustration has the chassis plugged into the AC neutral/gound side. Another variation appears on page 105 in "Ham Radio Projects" 1968 by Bert Simon, a circuit which looks even more scarry since you only plug into the hot leg of the AC outlet, and then ground the chassis to earth ground. I do not know how I lived to tell you now that it was my first rig! There is a one-tube rig on page 99 of "Ham Projects..." which uses a 6AV5 but that is not the circuit I see in this unkown 6L6 rig. Let me know if you know of a source for this single 6L6 transmitter. Nothing in either of the books mentioned has one like this. Other clues: it has three rf (air core) chokes, no other iron core choke, uses two variable condensers, keys thru one of these chokes to pin 8. Another choke goes from the antenna center pin to the chassis ground. The 3 rf chokes used appear to be identical. Bill / K6TAJ |
On closer examination again, I do now see a couple of small diodes (both have
the number 205) which were hiding behind some black spaghetti pushed up against them. This little homebrew seems to have been carefully assembled and I have no reason to believe that the 6L6 is not the correct tube. The little rig does work, but, as mentioned, the CW note was quite distorted and unacceptable. How would one go about trouble shooting this problem. At this point I have limited bench equipment , but might consider acquiring some. An oscilloscope is high on the want list. Can you point to a part of the circuit which would result in this very chirpy and wobbly CW tone. I would have to fire it up again to remember how best to describe the sound of this signal. Bill K6TAJ Roger and Ute Brown wrote: Bill, It sounds like you've been around awhile and have built some stuff in the past. Surely you can look at the circuit and figure out what is powering the thing. Put your meter into that thing and start measuring voltages (from the line cord, through the transformer and on...) Of course, if you find "any" DC - you've got a diode someplace. Take some paper and draw out the schematic (can't be to hard for one tube circuit). That will show you what you have. Check the tube base wiring against the 6L6 and see if everything goes to the correct pins for such a tube. It's possible you should have a tube which sports a rectifier (diode section) and another tube in the same envelope). At any rate - a part by part inspection resulting in a schematic will tell all! It's rather elementary. I'd be interested to hear what you find. Good luck, Roger, KL7Q zeno wrote in message ... I came across a cute little homebrew CW transmitter utilizing only a single 6L6. Mostly made from radio and audio junkbox parts, it does seem to work. I put it on the air briefly with its 40 meter Xtal and monitored the signal on another antenna. Sounds kind of chirpy, actually worse than chirpy. Needs some kind of work or upgrade or correction. I did some web searching but could not actually come up with a schematic for this rig, probably out of some old magazine or something. I do not quite understand how it works without a power supply rectifier. There is nothing under the hood which looks like a diode or selenium rectifier. Anyone have a clue as to this circuit. I am kind of new to this. How might I proceed to make this little rig into a useable QRP unit. I think it probably makes something under 10 watts, and the cw sounds goofy, wimpy, and wobbly. It is someone's old nice lay out failure, but it would be a fun challenge to convert it into something useful. Anyone seen a circuit for a singl 6L6 rig?...who knows maybe it has the wrong tube in there. Hmmmm....how to do the detective work on this???? I have a certain nostalgia for simple one tube rigs, when I was a novice in the early 50s as a kid I built this crazy rig with a single 117N7 that worked great with my very compromised end-fed random wire. I have recently found the schematic for that one, but it seems kind of crazy to build that one again, but who knows....the schematic for the 117N7 rig can be found on page 38 of "Radio For The Millions", 1945 Popular Science Publishing Co. Inc. This illustration has the chassis plugged into the AC neutral/gound side. Another variation appears on page 105 in "Ham Radio Projects" 1968 by Bert Simon, a circuit which looks even more scarry since you only plug into the hot leg of the AC outlet, and then ground the chassis to earth ground. I do not know how I lived to tell you now that it was my first rig! There is a one-tube rig on page 99 of "Ham Projects..." which uses a 6AV5 but that is not the circuit I see in this unkown 6L6 rig. Let me know if you know of a source for this single 6L6 transmitter. Nothing in either of the books mentioned has one like this. Other clues: it has three rf (air core) chokes, no other iron core choke, uses two variable condensers, keys thru one of these chokes to pin 8. Another choke goes from the antenna center pin to the chassis ground. The 3 rf chokes used appear to be identical. Bill / K6TAJ |
Chirp can be caused by different causes.
1. The crystal may simply change frequency when first loaded. Try a different crystal, or try the crystal in a different transmitter. 2. Feedback may be incorrect. Too much feedback can cause chirp. Depending upon the circuit, you can change feedback by varying the capacitance between grid and cathode. 3. Voltage stabilization. A stable voltage is less likely to chirp. Sometimes varying the screen voltage will help make the oscillator less likely to drift. Draw your circuit out and match it to one in the older Radio Amateur Handbook. Oscillator circuits are as simple as the Model T. Colin K7FM --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04 |
Chirp can be caused by different causes.
1. The crystal may simply change frequency when first loaded. Try a different crystal, or try the crystal in a different transmitter. 2. Feedback may be incorrect. Too much feedback can cause chirp. Depending upon the circuit, you can change feedback by varying the capacitance between grid and cathode. 3. Voltage stabilization. A stable voltage is less likely to chirp. Sometimes varying the screen voltage will help make the oscillator less likely to drift. Draw your circuit out and match it to one in the older Radio Amateur Handbook. Oscillator circuits are as simple as the Model T. Colin K7FM --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04 |
zeno wrote:
On closer examination again, I do now see a couple of small diodes (both have the number 205) which were hiding behind some black spaghetti pushed up against them. This little homebrew seems to have been carefully assembled and I have no reason to believe that the 6L6 is not the correct tube. The little rig does work, but, as mentioned, the CW note was quite distorted and unacceptable. How would one go about trouble shooting this problem. At this point I have limited bench equipment , but might consider acquiring some. An oscilloscope is high on the want list. Can you point to a part of the circuit which would result in this very chirpy and wobbly CW tone. I would have to fire it up again to remember how best to describe the sound of this signal. Bill K6TAJ The very first place to go is to check all of the chassis grounds. If solder lugs are screwed to the chassis, loosen them and then retighten them. If the octal tube socket has a ground ring, and metal ears as many do, loosen its screws, and retighten them. Clean and lube the wipers of any trimmer caps or air variable tuning caps. Clean up the pins and socket for the crystal. Next would be any electrolytics in the circuit. And, of course, any paper capacitors. If there are any "dogbone" resistors, get rid of them and replace them with "modern" carbon composition resistors. A lot of faults can be found by just listening to the note on a receiver, and wiggling stuff around. -Chuck Harris |
zeno wrote:
On closer examination again, I do now see a couple of small diodes (both have the number 205) which were hiding behind some black spaghetti pushed up against them. This little homebrew seems to have been carefully assembled and I have no reason to believe that the 6L6 is not the correct tube. The little rig does work, but, as mentioned, the CW note was quite distorted and unacceptable. How would one go about trouble shooting this problem. At this point I have limited bench equipment , but might consider acquiring some. An oscilloscope is high on the want list. Can you point to a part of the circuit which would result in this very chirpy and wobbly CW tone. I would have to fire it up again to remember how best to describe the sound of this signal. Bill K6TAJ The very first place to go is to check all of the chassis grounds. If solder lugs are screwed to the chassis, loosen them and then retighten them. If the octal tube socket has a ground ring, and metal ears as many do, loosen its screws, and retighten them. Clean and lube the wipers of any trimmer caps or air variable tuning caps. Clean up the pins and socket for the crystal. Next would be any electrolytics in the circuit. And, of course, any paper capacitors. If there are any "dogbone" resistors, get rid of them and replace them with "modern" carbon composition resistors. A lot of faults can be found by just listening to the note on a receiver, and wiggling stuff around. -Chuck Harris |
| All times are GMT +1. The time now is 01:58 PM. |
Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
RadioBanter.com